1. Field of the Invention
The invention relates in general to a shock isolation structure applied in an optical disc drive, and more particularly to a shock isolation structure applied in an optical disc drive which effectively isolates external impact when the optical disc drive is under horizontal installation or vertical installation.
2. Description of the Related Art
With the wide application of pictures, movies, music and computer software, high capacity optical disc has become an important software carriage to people living in today's society where science and technology are advancing rapidly. The optical disc, which can be further divided into CD and DVD, are widely used and beloved due to their features of large capacity, small size and safety in data storage. Therefore, the optical disc drive which can read the CD and DVD also becomes an essential piece of the equipment of a personal computer.
Referring to FIG. 1, an exploded 3-D diagram of a conventional optical disc drive with shock isolation structure is shown. In FIG. 1, the optical disc drive 10 includes a base 11, a traverse 12 and four shock isolation structures 13. The shock isolation structure 13 applied in an optical disc drive is disposed between the base 11 and the traverse 12 has a through hole 13a. The base 11 has four sleeve columns 14 received in the through hole 13a. The sleeve column 14 has a screw hole 14a for a screw 15 to be screwed into from the opening of one end of the through hole 13a when the shock isolation structure 13 is mounted on the sleeve column 14. The traverse 12 has four traverse's extension portions 12a. The embedding aperture of the traverse's extension portion 12a is for the shock isolation structure 13 to be embedded into. The optical disc drive 10 further includes a spindle motor 12b disposed on the traverse 12 for rotating an optical disc.
As shown in FIGS. 2A-2B, the shock isolation structure 13 at least includes a bottom portion 13b, a neck portion 13c and a top portion 13d. The neck portion 13c joints the bottom portion 13b and the top portion 13d. The bottom portion 13b, the neck portion 13c and the top portion 13d have a through hole 13a. The through hole 13a runs through the top surface of the top portion 13d and the bottom surface of the bottom portion 13b along the z-direction. The neck portion 13c is embedded into the embedding aperture of the traverse's extension portion 12a, so that the shock isolation structure 13 can moveably support the traverse 12 as shown in FIG. 2C.
Referring to FIG. 2B again, in the neck portion 13c, the outer peripheral 17a and the inner peripheral 17b of any of the ring-shaped cross-sections 17 using the z-direction as the normal form two concentric circles. The ring-shaped cross section 17 has a wall thickness K on the path starting from the circular center O2 and extending along the x-direction. The ring-shaped cross section 17 also has a wall thickness K on the path starting from circular center O2 and extending along the y-direction. Therefore, the neck portion 13c of the shock isolation structure 13 has a wall thickness K on any direction perpendicular to the z-direction.
Due to the differences of design and application, the optical disc drive can be installed in a computer according to horizontal installation or vertical installation. Suppose the optical disc drive 10 of FIG. 2C uses the x-direction as the gravity direction and adopts vertical installation. The neck portion 13c of the shock isolation structure 13 has an even wall thickness K, so the shock isolation structure 13 is incapable of providing a better shock isolation, resulting in a poor shock isolating performance against external impact. Worse than that, the wall thickness of the neck portion 13c along the x-direction would have a large deformation after receiving the external impact, causing the wall thickness of the neck portion 13c along the x-direction to be reduced, severely affecting the shock isolating ability of the shock isolation structure 13.
As shown in FIG. 3, the optical disc drive 10 further includes a tray 12c for carrying the optical disc 19 to enter or leave the optical disc drive 10 along the y-direction. When the optical disc drive 10 uses the x-direction as the gravity direction and adopts vertical installation, the gravity direction of the traverse 12 is the x-direction. The direction of the x-axis of the shock isolation structure 13 of FIG. 1 is easily distorted, causing the center of the optical disc 19 to shift downwardly for a distance of D. Consequently, the lower edge of the optical disc 19 would scrap the tray 12c and the base 11 when the optical disc 19 is rotated by the spindle motor 12b of FIG. 1. Besides, in order to isolate the external impact, the shock isolation structure 13 is normally designed to be very soft. When the horizontally installed optical disc drive 10 receives a larger external impact, the optical disc 19 would easily vibrate up and down. Under such circumstances, the optical disc 19 is more likely to scrap the bearing surface of the tray 19.